[Python] How to work with try and except in python?

This program has to analyze student numbers and if they are correct write them to one list and if not write them to another list. They are correct if they have eight digits and contain only numbers.

I however have no idea what to type when it comes to the try and except part.

If anyone could help, I would greatly appreciate it!

Valid_file = "ValidNumbers.txt"
Invalid_file = "InvalidNumbers.txt"
Data_file = "Data.txt"

def analyse_students(Data_file):
lenth = len(Data_file)
total = 0
try:

except:

return 0

def read(Data_file):
count = 0
student_list = []
try:
open(Data_file)
except:
print("Couldn't append file", Valid_file)
return count, student_list

def write(student, status):
if status:
try:
open(Data_file)
except:
print("Couldn't append file", Invalid_file)

count, student_list = read(Data_file)

print("Number of lines read", count)

for student in student_list:

print("See output files")

Continue reading...